Dynamic childbirth simulator for teaching maternity patient care

ABSTRACT

A programmable patient simulator for teaching maternity patient care includes a life size manikin with a pelvis, vaginal canal, uterus, placenta, umbilical cord, and a fetal doll from which heart sounds are emitted. A programmable electro-pneumatic system controls the simulated uterine contractions, position of the uterus, rupture of membranes, expulsion of fetal doll, and fetal heart rate during labor and delivery sequence. The invention described herein was made in the course of work under a grant or award from the Department of Health, Education and Welfare.

United States Patent [191 Knapp et al.

[ DYNAMIC CHILDBIRTH SIMULATOR FOR TEACHING MATERNITY PATIENT CARE [75]Inventors: Charles F. Knapp; George S. Eades,

both of Lexington, Ky.

[73] Assignee: University of Kentucky Research Foundation, Lexington,Ky.

[22] Filed: Nov. 5, 1973 [21] Appl. No.: 412,757

Related US. Application Data [62] Division of Ser. No. 308,542, Nov. 21,1972.

[52] US. Cl. 35/17 [51] Int. Cl. 60% 23/32 [58] Field of Search 35/17[56] References Cited UNITED STATES PATENTS 2,551,433 5/l95l Graves35/17 [111 3,826,019 51 July 30, 1974 Primary Examiner-Harland S.Skogquist Attorney, Agent, or Firm-William E. Sherwood [5 7] ABSTRACT Aprogrammable patient simulator for teaching maternity patient careincludes a life size manikin with a pelvis, vaginal canal, uterus,placenta, umbilical cord, and a fetal doll from which heart sounds areemitted. A programmable electro-pneumatic system controls the simulateduterine contractions, position of the uterus, rupture of membranes,expulsion of fetal doll, and fetal heart rate during labor and deliverysequence. The invention described herein was made in the course of workunder a grant or award from the Department of Health, Education andWelfare.

3 Claims, 13 Drawing Figures PAIENIEH JUL 3 01974 SHEET 2 OF 6 A NON SNPAIENTED M3019 3. 826'. O l 9 saw nor a Bul m a JUL30I974 SHEET 5 OF 6FIG. 7

FIG. 6

DYNAMIC CI-IILDBIR'II-I SIMULATOR FOR 7 TEACHING MATERNITY PATIENT CAREThis is a division of application Ser. No. 308,542 filed Nov. 21, 1972.

BACKGROUND OF THE INVENTION The training of students in the art ofmaternity patient care has long been handicapped by the artifical natureof the construction and operation of the models which are employed bythe instructor to illustrate the sequence of labor and delivery inchildbirth. For example, models of the type shown in Jacobs U.S. Pat.No. 2,127,774 and Graves U.S. Pat. No. 2,551,433 lack realism in thatthe fetal doll must be manually moved by the instructor and no closesimilitude to the real life steps of childbirth can be taught to thestudent, due in large part to the non-dynamic nature of the equipment.

Moreover, optimum value of the instruction being offered requires thatthe student handle the model as by palpating the uterus, listening tothe heart beat of the doll, and observing the degree and frequency ofuterine contractions. Preferably, this also requires the use of a lifesize model of manikin having a natural appearance and providing to thestudent a life like tactile sensation when being handled. It is apurpose of the present invention to provide an improved childbirthsimulator in which these and other disadvantages of conventionalequipment will be overcome and by means of which a more realistic andaccurate teaching of maternity patient care may be given to the student.

SUMMARY The invention is embodied in a dynamic manikin simulating thetorso of a pregnant human female and in which a fetal doll is locatedwithin a uterus housed in the manikin. Automatic means for controllablyapplying fluid pressure to the uterus serves to move the doll from theuterus and from the manikin, and the operation of this means is used tosimulate labor during childbirth and to provide instruction for studentsin the art of maternity patient care.

Among the objects of the invention are the provision of an improvedtraining device for teaching maternity patient care; the provision of animproved method of teaching maternity patient care; the provision of afetal doll; the provision of an improved uterus device; the provision ofan improved manikin; the provision of a placenta with attached umbilicalcord and amniotic sac; the provision of means simulating the breaking ofan amniotic sac; and the provision of an improved method ofmanufacturing the several elements of the training device.

These and other objects and advantages of the invention will become moreapparent as the description proceeds and when considered in conjunctionwith the accompanying drawings in which FIG. 1 is a diagrammatic view ofa system for effecting responses in the dynamic -manikin during theteaching procedure.

FIG. 2 is a portion of the electrical circuit under the control of theinstructor at the control console.

FIG. 3 is a longitudinal sectional view of the manikin with parts shownin elevation.

FIG. 4 is an end elevation of the manikin indicating the position of thepelvic bone.

FIG. 5 is a side elevation view of the uterus.

FIG. 6 is a face view of the fetal doll with interior parts indicated bydotted lines.

FIG. 7 is a back view of the doll of FIG. 6.

FIG. 8 is a diagrammatic view indicating the molding of the placenta andshowing the placenta with attached umbilical cord and amniotic sac.

FIG. 9 is a diagrammatic view of-the uterus and its associated membersin position within the manikin.

FIG. 10 is a chart indicating the timed rocking of the uterus of FIG. 9during the teaching procedure.

FIG. 11 is a chart indicating the timed cervical dilation and positionof the doll during the teaching procedure.

FIG. 12 is a chart indicating timed intra uterine prestuated inaccordance with a prearranged pattern which represents physiologicaldata offering the maximum of beneficial instruction to the student, itbeing understood that instructor-operated override controls may beemployed to aid in the instruction procedures. A conventionaltwo-channel data track follower 10 (such as the Date-Trak available fromResearch, Inc.) delivers a voltage proportioned to the curves scribed onits rotating drum through conductors ll, 12, and upon closing of aswitch 8 will also establish a circuit through conductor 13. Conductors11 and 12 lead respectively to electro-pneumatic transducers l4 and 15(such as the type available from Conoflow Corp.) through conventionalmatch packs l6, 17 serving to provide current supply consistent with therating of the transducers. The conductor 9 extending from the controlconsole circuit of FIG. 2 is connected to a heart sound simulator 18from which a conductor 19 leads to a speaker 111 (FIG. 6) embedded inthe fetal doll, as later to be described.

A compressed air reservoir 20 with a cut off valve 21 and with separatethrottling valves 22, '23 supplies air through conduits 24, 25 to thevalves associated with and controlled by the transducers. Fromtransducer 14, which governs the operation of the uterus rocking member26, later to be described, a conduit 27 leads to a conventionalFairchild-Hiller ratio relay 28 which may be adjusted as by means of amanually operable control .29. A conduit 30 in parallel with conduit 24also leads to this relay and from this relay a conduit 31 leads to therocking member; venting of thus described pressure system being throughthe vent 32 of the transducer housing,

Transducer 15 which governs the pressures applied to the uterus,includes a vent 33 in its housing as well as a conduit 34 leading to asecond ratio relay 35 having a control means 36. A conduit 37 inparallel with conduit 25 leads to the relay 35 and from relay 35 aconduit 38 leads to the fundus chamber of the uterus. In addition, abranch conduit 40 controlled by transducer 15 leads to a third ratiorelay 41 having a control means 42. A conduit 43 in parallel withconduit 37 also leads to this third relay and from the relay a conduit44 leads to the inner chamber of the uterus.

Conductor 13 from the data track leads to a suitable motor 50 driving apump 51 which draws water from a supply 52 and at an appropriate timedischarges the same through conduit 53 and into a receptacle within themanikin simulating the amniotic sac. Moreover, for cervix thickening andthinning purposes, a suitable source 55 of compressed air leads througha conduit 56 to the cervix and is provided with a suitably actuatedbleed valve 57 adapted to vent the conduit 56 in a controlled manner.

The Manikin For realism in teaching, as well as for economicconsiderations since the equipment is intended for repeated usages, thematerials used in constructing the fetal doll, placenta, uterus andmanikin satisfy the requirements of being strong and durable, beingcompatabile with each other, and significantly having the feature ofrepresenting life like proportions, appearance, and tactile sensations.In constructing the manikin the following method is preferred.

A live model was placed in proper position on a delivery table and amolding material comprising Silastic A,

v available from Dow Corning Co., was mixed and poured over her bodyfrom the knee line to the breast line. After this material set up toprovide an initial mold, a second layer comprising Silastic B materialwas poured on the initial mold to add strength and a plaster embossedcloth was applied over the layer of Silastic B to add rigidity to thethus formed initial mold. When the materials were sufficiently cured theinitial mold having an open lower portion, where the body was resting onthe table, was then removed from the live model. The interior of thisinitial mold was then painted with a creamy latex coating which whenremoved from the initial mold, and suitably reinforced, served as ahollow positive mold.

This hollow mold was then shaped to .provide the same proportions asthose of the live model and a negative mold of plaster material, such.as Microstone, was cast around the outer surface of the shaped positivelatex mold while lying upon a flat base. Thereafter, the latex positivemold was removed from the negative mold and the manikin as seen in FIGS.3 and 4 was constructed as follows.

First, a skin colored natural latex rubber (such as Cis- Isopreneavailable from Firestone Co. as S4-Latex) was mixed with a suitablecatalyst dispersion material and with silicon antifoam, and was paintedon the interior surfaces of the negative mold to provide a skin 61 forthe manikin. The natural skin coloration was achieved in the mannerherein described under Pigmentation Procedures.

The skin 61 within the plaster mold was painted with a bonding agent,such as a polyurethane activated coating, and a A; inch sheet 64 ofpolyurethane foam which has been treated in a sodium hydroxide solutionwas placed in firm contact with the skin 61. Next to simulate adiposetissue and to give a realistic tactile sensation to the student a inchlayer 65 of polyvinyl chloride gel was deposited upon the foam sheet.(This adipose tissue layer preferably extends from the breast area tothe thighs and in the abdominal region well toward the back of themanikin.) The treatment of the foam sheet with the solution and thetreatment of the skin with the bonding agentmeanwhile serves to permitthe gel to pass through pores of the foam sheet and to become bonded tothe skin of the manikin.

A pelvic bone 66, as best shown in FIG. 4, was formed as follows. A realfemale pelvis of a laboratory skeleton was coated numerous times with avulcanized latex to produce a flexible but stiff mold. Upon beingremoved from the actual pelvis the stiff mold was filled with afiberglass-resin material including sawdust and white pigment and uponcuring andremoval from the stiff mold the pelvic bone was ready forinsertion into the manikin. Meanwhile by means of a separate positivemold, representative of the volume and shape dimensions of the uterusand vaginal opening, an imitation uterus was provided and on which thecombined birth canal 62 and open-top receptacle member 63 was formed bypainting a coat of natural latex.

The pelvic bone and imitation uterus were then positione'd within thehollow manikin and the entire remaining space within the plaster mold ofthe manikin was filled with flexible polyurethane foam 67, the birthcanal meanwhile having been attached to the skin of the manikin at thevaginal opening by additional coats of latex. After curing of the foam,a section of the same was cut away to provide access to the imitationuterus and to leave a space later to receive the uterus rocking member.Then the imitation uterus was removed leaving behind the receptaclemember 63 and birth canal 62 which readily slip from that imitationuterus. For purposes of collapsing the foam filled manikin and removingit readily from its encasing mold, the pelvic bone likewise is removedtemporarily and after the manikin is free of its mold, the pelvic boneis reinserted after which the manikin is attached at its lower side tothe base plate 60 with an aperture therein. As will be apparent, themanikin now contains a space into and from which the simulated uterusforming a significant feature of the invention, can now be moved.

The electrical conductor 19 as well as the conduits 31, 38, 44 and 56(FIG. 1) are now extended through the foam 67 to terminate in detachablecouplings 129, 68, 69, 70 and 93 respectively. The water supply line 53likewise is extended through the foam 67 and has an open end at 72 lyingbeneath the pelvic bone and in open communication with the interior ofthe receptacle portion 63. The aperture in the base plate is then fittedwith a door member 75 hinged at 76 and adapted to be latched at 77 tothe base plate. This door carries a platform 78 mounting a bellows-likewedge 79 interposed between the platform and a pivoted cradle 80 whichis adapted to bear against the uterus-containing receptacle 63 when thebellows is inflated, and against the bias of a restoring means such asspring 81. This cradle is adapted to pivot through a suitable angle 0(FIG. 3) which may be as much as 30. A suitable flexible conduit 82 fromthe bellows is adapted to engage with couplng 68 after the manikin isprepared for a childbirth demonstration and before the door 75 islatched.

The Uterus A'preferred method for constructing the uterus involvesproviding a plaster positive mold representative of an actual full termpregnant uterus as regards size and shape and then painting the entiremold several times with natural latex rubber. A nylon mesh is wrappedaround the painted mold for reinforcement and more coats of latex arepainted until a thickness of about 8-10 coats is obtained to form theinner wall 90 (FIG. 5). A conventional zipper 91 extending substantiallyaround the entire wall periphery is then bonded to the wall with latexwith a gap being provided between the ends of the zipper, and thedeposited layer beneath the zipper is then cut. In addition, adistendable cervix portion 92 formed of a hollow generally annularshaped member of latex material and having a conduit 93 extendingtherefrom for connection to conduit 56 (FIG. 1) is fixed to the innerwall at the uterus opening, for a purpose later to be described.

A masking material such as a sheet of cellophane is then wrapped aroundthe larger portion of the uterus inner wall while still on the positivemold and with at least /2 inch being between the zipper and the adjacentedge of the masking material. A plastic air coupling 94 is-positioned onthe cellophane and extends outwardly and nylon mesh with the aircoupling projecting therethrough is placed over the entire cellophanesheet after which about 8 coats of latex are painted over this mesh toform the middle wall 95 of the uterus and which middle wall will laterballoon outwardly from the inner wall when air is supplied throughcoupling 94.

Thereafter, a narrow strip of cellophane is wound in generally spiralfashion around the middle wall and with a header strip of cellophanetouching the turns of that narrow strip. A second air coupling 96 ispositioned on the header strip projecting outwardly and another layer ofnylon mesh is placed over the described assembly. Thereafter, about 8coats of latex are painted over this mesh to form the third or outerwall 97. As will be noted, this third wall, representing the fundus ofthe uterus, is attached in a spiral fashion to the middle wall, but isnot attached to the inner wall. Moreover, the manifold portion 98permits air to enter the spiral spaces inside the outer wall in afashion permitting a realistic contraction of the uterus. Having thusfabricated the uterus on the mold the assembly is cured in an oven forabout 30 minutes at 220F. and upon opening of the zipper the uterusmember is removed from the mold and is ready for use within the manikin,an aperture 131 meanwhile being formed in the gap between the ends ofthe zipper.

The Fetal Doll A preferred method for constructing the fetal dollinvolves using a dead full-term fetus coated with vaseline for themaking of a mold as follows. The fetus is placed on its back in a boxand Silastic A is poured around the fetus until approximately half ofthe fetus is covered whereupon indexing means such as large marbles arehalf submerged in the thus formed half mold at its upper face and aparting coating of vaseline is coated over the face and marbles. ThenSilastic A is poured over the remainder of the fetus to complete thesecond half of the mold. After setting of the material, the mold halvesare separated and the fetus removed therefrom. The thus formed two-partinitial negative mold is cleaned and coated with vaseline and Silastic Ais filled into the lowerhalf of the negative mold with particular carebeing taken to fill the hand and feet spaces thereof.

Thereafter, the other mold half with a filling aperture provided at thehead region is filled to the described first half of the filled mold andSilastic A is forced through the aperture until the mold cavities arefilled.

This results in a solid Silastic fetus which upon being removed from themold halves then serves for the preparation of a two part negative moldformed of Microstone and cast in the same way as the initial negativemold of Silastic was prepared.

Having available the plaster negative mold the interior surfaces of themold halves are painted with a solution of calcium nitrate and the twohalves with entry parts extending into the mold spaces corresponding tothe heel of each foot are sealed together and placed in a rotatable jig.Askin colored natural latex rubber, such as Cis-Isoprene was thenprepared as indicated under Pigmentation Procedures and was poured intothe sealed mold through one port until the mold interior is filled, theother port permitting expulsion of air. Upon closing of both portfollowed by periodic rotations of the jig a layer of skin for the fetaldoll is built up after which the unused portion of the fluid latex isdrained from the mold. The mold then is removed from the jig and placedin a curing oven for about 36 hours at about 120F. whereupon the moldparts are detached leaving the hollow fetal doll of live sizeproportions and appearance with the skin covering the same.

The back of the doll is then cut longitudinally and a zipper 101 isbonded to the skin along the opening by painting on several coats oflatex. With the doll opened, the inside of its body portion is coatedwith polyurethane as described with respect to the manufacture of themanikin. The fetal skull is prepared as follows. The skull of a deadfull-term fetus is covered with latex to produce a flexible but stiffpositive mold which after removal from the fetal skull is partiallyfilled with marine resin and rotated to build up a layer 102 about 1/4inch thick within the positive mold. Thereafter, the positive mold isremoved and the top portion of the hollow skull of resin is filled withpolyvinyl chloride gel and the lower portion 104 is filled with SilasticA. As shown in FIG. 6, the lower skull portion includes a ball joint 105encased in the silastic material and attached to a wooden or fibreglassrod 106 simulating a spine. At the lower end of the rod a plate 107joined to the rod with another ball joint 108 is provided, the purposeof which will later appear. The resin layer 102, moreover, is cut atvarious places to provide flexibility during passage of the fetal dollhead through the birth canal 62 of the manikin and includes the anteriorand posterior fontanels 109, 110 respectively which can be identified bydigital inspection during the instruction of the student.

With the simulated skull and spine thus prepared, it is placed in properposition with the opened doll and a speaker 111 is suspended in thechest cavity by means of nylon thread 112. This speaker has attachedthereto the electrical cord 113 which projects about three inches fromthe navel 114 of the doll and terminates in a speaker-jack 115 (FIG. 6).Following installation of the speaker the doll is then placed in theposition of FIG. 7 and polyvinyl chloride gel is poured into the doll tofill all space therein after which the zipper 101 is closed. The filleddoll which may weigh about seven pounds is then replaced in themicrostone negative mold to insure fidelity to its original shape andafter curing in the mold is removed and is ready for use with theabove-described uterus.

The Placenta, Amniotic Sac, and Umbilical Cord A two part negative mold120, 121 (FIG. 8) of Silastic A and B is made from a real placenta byfollowing a molding procedure as taught with the molding of the fetaldoll. The placenta is then removed and an elongated flexible cord 123including electrical conductors and of a size and length similar to anactual umbilical cord is passed through an opening in the mold 120. Atone end the cord terminates in a coupling 124 adapted for attachment tothe jack 115 of the fetal doll and at the other end the core terminatesin a coupling 125. A disc shaped piece of fabric 126 is attached to thecord adjacent the coupling 125.

The lower mold 120 is then filled with polyvinyl chloride gel containingred pigment and surrounding the fabric. Then a preshaped latex membrane126 simulating an amniotic sac and of sufficient size to enclose all ofthe fetal doll (except at the top of its head portion, FIG. 9) is placedover the thus filled half 120 of opening 131 of the zipper gap and willbe connected to conductor 19 to provide for heart beat transmissionduring the teaching procedure.

Pigmentation Procedures For added value in teaching it is important thatthe fetal doll and manikin not only feelrealistic, but also appear thesame. In contrast with conventional dolls made of leather and manikinsmade of wood or metal the present invention is able to achieve thedesired realism. A preferred method for securing the life-like color ofthe manikin includes adding to 2,000 grams of the latex and mixing for10 minutes therewith a semifluid paste comprising about 25 grams ofwhite titanium dioxide pigment and about 78 grams of peach titaniumdioxide pigment mixed dry with each other and stirred in just enoughwater to form the paste. This pigmented latex is with a suitablecatalyst dispersion prior to being applied to the mold surfaces and at atime not more than three hours before being so applied.

In making the fetal doll 2,000 grams of the latex has added thereto andsimilarly mixed a semi-fluid paste comprising the same amounts of thewhite and peach pigments together with about 7.4 grams of red titaniumdioxide and about 3.3 grams of blue titanium dioxide, all of thepigments being available from American Crayon Co.

Method of Operation Having available the manikin and associated elementsfor teaching maternity patient care, the uterus is opened with thezipper and upon being lubricated with a coating of suitable material thefetal doll and placenta are placed therein with the umbilical cord 123attached and the conductor 130 extended to the exterior of the uterus.as best shown in FIG. 9. After closing the zipper, the assembly is thenplaced in the manikin through the open door 75 and the uterus ispartially encased by the flexible receptacle portion 63 and with thehead of the doll supported adjacent the pelvic bone of the manikin. Theelectrical connections to conductor 19 is made and the several air lineconnections between the uterus and the conduits at 69, and 93 arecompleted. The air line connection to wedge 79 is completed and the dooris closed thus placing the manikin in readiness for a cycle of teachinginstruction and providing an additional support to the uterus by meansof the pivoted cradle member 80.

The physiological data which is programmed on the dual channel datatrack10 includes response to be made by the uterus during the simulated laborand delivery. A second channel controls the air pressures which are tobe applied to the uterus between its respective walls to simulate amuscular action and the contractions leading to expulsion of the fetaldoll. Such data are illustrated in FIG. 12 wherein the frequency ofcontraction and the amplitude during each first stage, advanced firststage, and second stageof labor are represented by traces 140, 141 and142.

Similarly, in FIG. 11, the position of the fetal doll and the dilationof the cervix are plotted as curves 143 and 144 against a time intervalof eight hours. The actual trace 145 on the second channel of the datatrack is represented in FIG. 13 as a consolidation of traces 140 to 144and indicates pressures applied to the uterus through conduits 38 and 44as plotted against time. As will be understood, the transducer 15 inassociation with the relays 35 and 41 governs these applied pressures inaccordance with the signal which it is receiving from that secondchannel of the data track.

A further phase of instruction includes the teaching of the positioningof the uterus to insure that the head of the doll is properly directeddownwardly into the pelvic bone space in preparation for delivery. Ashifting or rocking of the uterus through angle is generally desirableand the curve 146 of FIG. 10 indicates such angle with respect to time.The cradle inside the manikin accordingly is actuated by the wedge 79when compressed air is supplied thereto under control of transducer 14and relay 28. The signal to the transducer is provided by the trace onthe first channel of the data track.

Another phase of instruction involves a simulated breaking of water fromthe amniotic sac and which is initiated when a switch 8 on the revolvingdrum of the data track actuates the motor 50. When this occurs water issupplied through conduit 53 in the manikin and flows initially into thereceptacle portion 63 until its level is high enough to flow out of thebirth canal 62.

Still a further phase of instruction involves the dilation of the cervixand involving a deflation of the annular member 92 (FIG. 5) of theuterus. When compressed air is supplied to this member through conduit56 a relatively rigid doughnut shaped appendage to the uterus isprovided and which can be noted by digital examination by the student.

Such would be the case at an early stage of the curve 144 (FIG. 11).Later, this air is permitted to bleed gradually from member 92 throughvalve 57 and as this occurs the member 92 becomes flattened and dilatedto a position such as indicated by 92 A permitting the head of the dollto move from the uterus.

Referring now to H6. 2 wherein the chief elements of the electricalsystem are shown, it will be appreciated that a conventional console(not shown) is remotely placed with respect to the manikin, and that aconventional audi-pointer means (not shown) may be employed by theinstructor to provide information to the students pertinent to the laborand delivery exercise.

One suitable electrical circuit for operating the apparatus inaccordance with the invention includes conductors 200, 201 extending toa 110 volt A.C. source and with a switch 202 which when closed energizesa neon lamp 203 on the console control board. Simultaneously, closing ofswitch 202 energizes the match power packs l6 and 17 in readiness forsignals later to be received from the data track 10. Subsequent closingof a second switch 204 energizes the coil of relay 205 closing itsnormal open contacts and energizing lamp 206. Simultaneously A.C. poweris supplied to the heart beat amplifier 207 in readiness for signalslater to be received from the heart beat simulator l8 and at the sametime A.C. power is supplied to the heart beat power supply 209. Theheart beat simulator l8 preferably is of the type generally defined inNASA Tech Brief No. 67- l 0239, but as such forms no part of the presentinvention.

Subsequent closing of a third switch 210 in both the A.C. and DC.circuits serves to energize the coil of relay 211, and to open itsnormally closed contacts in the A.C. circuit. This closing of switch 210also completes the DC. circuit from the DC. heart beat power supply 209to the heart beat simulator l8 and from that heart beat simulator to theheart beat amplifier 207. This heart beat power supply preferablyfunishes 13.5 volt DC. current to the simulator and a manually operablepotentiometer 215 is included in the simulator circuits to permit theinstructor to vary the heart beat frequency for teaching purposes.

As will be apparent, upon the closing of switch 210 the simulator nowsupplies an audio signal to amplifier 207 which amplifies the same andpasses it through the connection 19 to the manikin, thence through theconductor 130 to the placenta and thence through the umbilical cord 123to the speaker 111 in the fetal doll.

With the heart beat now audible, a fourth switch 216 is now closedwhereupon lamp 217 is illuminated. Thereupon, a fifth switch 218 isclosed to illuminate lamp 219 and simultaneously to supply power to thecoils of motor 50 which drives pump 51, and to place this pumpingarrangement in readiness for operation either through switch 8associated with the data track or through an instructor over-ride switch221. For the purpose of varying the rate of flow through conduit 53leading to the manikin a potentiometer 222 is provided to control thespeed of motor 50.

As will be understood, the paper tracks used on the drum of member canbe changed to simulate either normal conditions as reflected by thecomposite curve 145 of FIG. 13, or by substituting a curve representingabnormal childbirth conditions for teaching purposes. Moreover thelength of the exercise can be adjusted by using a, different gear trainto control rotation of the drum in the data track follower.

With the control system in readiness as above described and upon closingof the operating switch 223 p the data track drum begins to turn and asindicated by FIG. 1 voltage signals proportional to the dual channeltracks are now sent to the already energized match power packs 16 and17. Tranducers l4 and 15 in association with the ratio relays 28, 35 and41 govern the flow of compressed air to the manikin. At the beginning ofthe exercise air at about one pound per square inch superatmospheric,herein called base pressure, is supplied to the uterus between the innerand middle walls and between the middle and outer walls thus snuglyencasing the placenta and fetal doll as shown in FIG. 9.

As signals from the channels of the data track are then received by thematch packs and passed on to the transducers, the pressures of airpassing through the ratio relays are varied according to the establishedprogram. Initially during the latent phase of labor the pressure in thespace between the outer and middle walls of the uterus is periodicallyincreased and then falls to the base pressure, the pressure between themiddle and inner walls remaining meanwhile at the base pressure value.This simulates the muscular contractions of normal labor and involves ahardening of the wall of the uterus and a thickening of the fundusportion thereof and at the same time involves increasing the intensityof the uterine contractions.

Simultaneously, air under pressure being supplied to the wedge 79 undercontrol of the first channel of the data track regulates the positionoccupied by the fetal doll and insures that the head of the doll isproperly positioned with respect to the space within the pelvic bonestructure of the manikin. As descent of the doll begins during thelatter portion of the latent phase the instructor insures that the airpreviously supplied to the cervix portion of the uterus is graduallyvented through valve 57 thus aiding in the dilation of the latex cervixas indicated in FIG, 11. Descent of the doll, moreover, is beingaccomplished by air now being supplied at increasing amplitude ofpressures to the space between the inner and middle walls of the uterusunder control of the second channel of the data track.

As will be understood, during this period of latent phase of labor thestudents are receiving instruction which may take the form of listeningto the fetal heart beat with a stethoscope, digital examination of thecervix, palpation of the abdomen of the manikin, and other usefultechniques. At an appropriate time during the descent of the doll switch8 on the data track closes and pump 51 begins to supply water to themanikin and the water level in the receptacle portion 63 begins to rise(FIG. 9). When this level reaches a prescribed height correspondinggenerally to the time the head of the doll moves through the opening ofthe amniotic sac 126 such water flows from the birth canal simulatingthe breaking of water.

Continued application of pressures of progressively higher amplitude andincreased frequency to the space between the inner and outer walls ofthe uterus then forces the doll from the uterus simulating the delivery.As will be understood, the pressure applied to the doll by expansion ofthe uterus space between the inner and outer walls thereof acts upon theplate 107 and is transmitted to the skull through the simulated spine106 thus forcing the head of the doll through the dilated cervix of theuterus.

Upon delivery of the doll, the student then disconnects the umbilicalcord from the doll at the speakerjack whereupon the heart beat speakeris silenced and other instruction simulating the actual handling of anewly delivered child may be conducted. Subsequently, the umbilical cordand its attached placenta and amniotic sac are drawn from the uterus andthe jack 129 is disconnected from the conductor 130. The switches 223,218, 216, 204 and 202 are then opened in sequence to restore the systemto inoperative condition and to avoid any damage to the heart beatsimulator.

The door 75 of the manikin is then opened and the conduit connections tothe wedge and to the uterus are disconnected, as is the connectionbetween conductors l9 and 130. Thereafter, the uterus is removed fromthe manikin and is in readiness for the next cycle of instruction.

Having thus described the apparatus and method of operation, it will beseen that the apparatus is suitable for use in many cycles of operationwithout replacement of parts, and that a high degree of similitude toactual childbirth phenomena is presented to the student.

Obviously, other modifications and variations of the present inventionare possible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

l. A training device of the type used in teaching maternity patient carecomprising, a placenta adapted to be placed in and later removed from asimulated uterus, a simulated umbilcal cord attached to said placentaand containing an electrical conductor adapted to be attached to a fetaldoll, said placenta having an electrical conductor extending therefromand adapted to establish communication from said cord to a point remotefrom said doll and placenta.

2. A placenta as defined in claim 1 having an amniotic sac attachedthereto and adapted to envelop substantially all of a fetal doll.

3. A placenta as defined in claim 1 and comprising a body portion formedof polyvinyl chloride gel.

1. A training device of the type used in teaching maternity patient carecomprising, a placenta adapted to be placed in and later removed from asimulated uterus, a simulated umbilcal cord attached to said placentaand containing an electrical conductor adapted to be attached to a fetaldoll, said placenta having an electrical conductor extending therefromand adapted to establish communication from said cord to a point remotefrom said doll and placenta.
 2. A placenta as defined in claim 1 havingan amniotic sac attached thereto and adapted to envelop substantiallyall of a fetal doll.
 3. A placenta as defined in claim 1 and comprisinga body portion formed of polyvinyl chloride gel.